Django 小实例S1 简易学生选课管理系统 9 创建课程模型(model)
Django 小实例S1 简易学生选课管理系统 第9节——创建课程模型(model)
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作者自我介绍：b站小UP主，时常直播编程+红警三，python1对1辅导老师。
对于课程模块，需要：
- 课程表
- 学生课程表：学生和课程的关系表
- 时刻表：课程上课时间设置
由于课程会有多个状态，这个可以先在constants.py中去记录好（即添加代码如下）
COURSE_STATUS = {
1: "未开始选课",
2: "开始选课",
3: "结束选课",
4: "结课",
5: "打分完成",
}
COURSE_OPERATION = {
1: "开始选课",
2: "结束选课",
3: "结课",
4: "给分",
5: "查看详情"
}
然后在course/models.py中导入下面会需要的所有库
from django.db import models
import datetime
from user.models import Student, Teacher
from constants import COURSE_STATUS, COURSE_OPERATION
1 添加课程模型
在course/models.py中添加代码如下
def current_year():
# refer: https://stackoverflow.com/questions/49051017/year-field-in-django/49051348
return datetime.date.today().year
class Course(models.Model):
credits = [
(1, 1),
(2, 2),
(3, 3),
(4, 4),
(5, 5),
]
semesters = [
("Autumn", "上"),
("Spring", "下")
]
name = models.CharField(max_length=50, verbose_name="课程名")
introduction = models.CharField(max_length=250, verbose_name="介绍")
credit = models.IntegerField(verbose_name="学分")
max_number = models.IntegerField(verbose_name="课程最大人数")
year = models.IntegerField(verbose_name="年份", default=current_year)
semester = models.CharField(max_length=20, verbose_name="学期", choices=semesters)
# 未开始选课， 1
# 开始选课，未结束选课 2
# 结束选课， 3
# 结课 4
# 已打完分 5
status = models.IntegerField(verbose_name="课程状态", default=1)
teacher = models.ForeignKey(Teacher, verbose_name="课程教师", on_delete=models.CASCADE)
def get_status_text(self):
return COURSE_STATUS[self.status]
def get_op_text(self):
return COURSE_OPERATION[self.status]
def get_current_count(self):
courses = StudentCourse.objects.filter(course=self, with_draw=False)
return len(courses)
def get_schedules(self):
schedules = Schedule.objects.filter(course=self)
return schedules
def __str__(self):
return "%s (%s)" % (self.name, self.teacher.name)
补充说明： get_status_text和get_op_text方法是为了方便在模板中调用。
2 添加课程时刻表模型
在course/models.py中添加代码如下
def weekday_choices():
weekday_str = ['周一', '周二', '周三', '周四', '周五', '周六', '周日']
return [(i+1, weekday_str[i]) for i in range(7)]
class Schedule(models.Model):
weekday = models.IntegerField(choices=weekday_choices(), verbose_name="日期")
start_time = models.TimeField(verbose_name="上课时间")
end_time = models.TimeField(verbose_name="下课时间")
location = models.CharField(max_length=100, verbose_name="上课地点")
remarks = models.CharField(max_length=100, verbose_name="备注", null=True, blank = True)
start_week = models.IntegerField(verbose_name="第几周开始")
end_week = models.IntegerField(verbose_name="第几周结束")
intervals = [
(1, "无间隔"),
(2, "每隔一周上一次")
]
week_interval = models.IntegerField(verbose_name="周间隔", choices=intervals, default=1)
course = models.ForeignKey(Course, verbose_name="课程名", on_delete=models.CASCADE)
def __str__(self):
s = "第%s周-第%s周 " % (self.start_week, self.end_week)
if self.week_interval == 2:
s += "隔一周 "
s += "%s %s-%s " % (self.get_weekday_display(), self.start_time.strftime("%H:%M"),
self.end_time.strftime("%H:%M"))
s += "在%s" % self.location
if self.remarks:
s += " %s" % self.remarks
return s
3 添加学生课程关系表模型
在course/models.py中添加代码如下
class StudentCourse(models.Model):
create_time = models.DateTimeField(auto_now=True)
with_draw = models.BooleanField(default=False)
with_draw_time = models.DateTimeField(default=None, null=True)
scores = models.IntegerField(verbose_name="成绩", null=True)
comments = models.CharField(max_length=250, verbose_name="老师评价", null=True)
rates = [
(1, 1),
(2, 2),
(3, 3),
(4, 4),
(5, 5),
]
rating = models.IntegerField(verbose_name="学生评分", choices=rates, null=True, help_text="5分为最满意，最低分是1分")
assessment = models.CharField(max_length=250, verbose_name="学生评价", null=True)
student = models.ForeignKey(Student, on_delete=models.CASCADE)
course = models.ForeignKey(Course, on_delete=models.CASCADE)
4 建立（更新）数据库
简单复述一遍，即在项目文件夹下打开命令行窗口，执行：
python manage.py makemigrations
python manage.py migrate
